**2. Biogas technology overview and status in Africa**

Biogas technology is viewed as one of the renewable technologies in Africa that can help eases its energy and environmental problems. To date, some digesters have been installed in several sub-Saharan countries, utilising a variety of waste such as from slaughterhouses, municipal wastes, industrial waste, animal dung and human excreta. Small-scale biogas plants are located all over the continent but very few of them are operational. In most African countries, for example, Burundi, Ivory Coast, and Tanzania, biogas is produced through anaerobic digestion of human and animal excreta using the Chinese fixed-dome digester and the Indian floating-cover biogas digester, which are not reliable and have poor performance in most cases (Omer and Fadalla, 2003). These plants were built for schools, health clinics and mission hospitals and small-scale farmers, in most cases by nongovernmental organisations. In Africa the interest in biogas technology has been further stimulated by the promotional efforts of various international organisations and foreign aid agencies through their publications, meetings and visits. Most of the plants have only operated for a short period due to poor technical quality. Table 3 gives a list of the African countries with biogas production units as at 2007. There is thus a need to introduce more

Anaerobic Biogas Generation for Rural Area Energy Provision in Africa 41

Some of the first biogas digesters were set up in Africa in the 1950s in South Africa and Kenya. In other countries such as in Tanzania, biogas digesters were first introduced in 1975 and in others even more recently (South Sudan in 2001). To date, biogas digesters have been installed in several sub-Saharan countries including Burundi, Botswana, Burkina Faso, Cote d'Ivoire, Ethiopia, Ghana, Guinea, Lesotho, Namibia, Nigeria, Rwanda, Zimbabwe, South Africa and Uganda (Winrock International, 2007). Biogas digesters have utilized a variety of inputs such as waste from slaughterhouses, waste in urban landfill sites, industrial waste (such as bagasse from sugar factories), water hyacinth plants, animal dung and human excreta. Biogas digesters have been installed in various places including commercial farms (such as in chicken and dairy farms in Burundi), a public latrine block (in Kibera, Kenya), prisons in Rwanda, and health clinics and mission hospitals (in Tanzania) (Winrock International, 2007). However, by far the most widely attempted model is the household biogas digester – largely using domestic animal excreta (Table 2). This is due to the fact that this technology is closely linked to poverty alleviation and rural development. The biogas produced from these household-level systems has been used mostly for cooking, with some

Global experience shows that biogas technology is a simple and readily usable technology that does not require overtly sophisticated capacity to construct and manage. It has also been recognized as a simple, adaptable and locally acceptable technology for Africa (Gunnerson and Stuckey, 1986; Taleghani and Kia, 2005). There are some cases of successful biogas intervention in Africa, which demonstrate the effectiveness of the technology and its relevance for the region. The lessons learned from biogas experiences in Africa suggest that having a realistic and modest initial introductory phase for Biogas intervention; taking into account the convenience factors in terms of plant operation and functionality; identifying the optimum plant size and subsidy level; and; having provision for design adaptation are key factors for successful biogas implementation in Africa (Biogas for better life, 2007).

**2.1 Challenges to biogas commercialisation in Africa and possible measures to** 

treatment for biogas production in developing countries are in Table 3.

aggravated by miscommunication and the lack of understanding.

The implementation of the biogas technology on large scale may be prevented or slowed down by a number of constraints. They may be grouped as follows: political, social-cultural, financial, informational, institutional, technical and training (Omer and Fadalla, 2003, Ni and Nyns, 1996). Some of the difficulties encountered in the development of anaerobic

There is lack of coherent biogas technology strategy in many sub-Saharan African countries despite the increase in the price of conventional fuel on a daily basis, and their rising demand mainly to technical and non-technical factors. The main contentious problems of biogas commercialisation in sub-Saharan African countries relate to economics and political will and many site-specific issues. Some of these issues are informed by local dynamics of perceptions; influenced by personal, social and institutional factors and beliefs, as well as internal conflicts, due to perceived environmental, social and ecological risks, that were

use for lighting.

**overcome them** 

Biogas technology has multiple beneficial effects.

Country Geographical characteristic Region No of small/ medium digester ( 100m3) No of Large scale digester (>100m3) Level of technology development Landlocked Coastal Botswana **\*** Southern Africa Several Few Low Burkina Faso **\*** West Africa Few - Low Burundi **\*** Central Africa Several Several High Cameroon **\*** Central Africa Few - Low Congo-Brazzaville **\*** Central Africa Several Few Low Côte d'Ivoire **\*** West Africa Several Few Low Egypt **\*** North Africa Several Few High Eritrea **\*** East Africa Few - Low Ethiopia **\*** East Africa Few - Low Ghana **\*** West Africa Several Few High Guinea **\*** West Africa Few - Low Kenya **\*** East Africa Several Several High Lesotho **\*** Southern Africa Few - Medium Malawi **\*** Southern Africa Few - Low Mali **\*** West Africa Several Few High Morocco **\*** North Africa Several - Medium Namibia **\*** Southern África Few - Low Nigeria **\*** West Africa Few Few Low Rwanda **\*** Central Africa Several Few High Sierra Leone **\*** West Africa Few - Low South Africa **\*** Sothern Africa Several Several High Sudan **\*** East Africa Few - Low Swaziland **\*** Southern Africa Several - Medium Tanzania **\*** East Africa Several Several High Tunisia **\*** North Africa Few - Low Uganda **\*** East Africa Few - Low Zimbabwe **\*** Southern Africa Several Few Medium

efficient reactors to improve both the biogas yields and the reputation of the technology. The development of large-scale anaerobic digestion technology in Africa is still embryonic, but with a lot of potentials.

Sources: Karekezi, (2002), Allafrica.com, (2000), Akinbami *et al*, (2001), Spore, (2004), Amigun and von Blottnitz, (2007).

Table 2. Countries with documented biogas producing units in Africa as at 2007

efficient reactors to improve both the biogas yields and the reputation of the technology. The development of large-scale anaerobic digestion technology in Africa is still embryonic, but

Burkina Faso **\*** West Africa Few - Low Burundi **\*** Central Africa Several Several High Cameroon **\*** Central Africa Few - Low

Brazzaville **\*** Central Africa Several Few Low Côte d'Ivoire **\*** West Africa Several Few Low Egypt **\*** North Africa Several Few High Eritrea **\*** East Africa Few - Low Ethiopia **\*** East Africa Few - Low Ghana **\*** West Africa Several Few High Guinea **\*** West Africa Few - Low Kenya **\*** East Africa Several Several High

Mali **\*** West Africa Several Few High Morocco **\*** North Africa Several - Medium

Nigeria **\*** West Africa Few Few Low Rwanda **\*** Central Africa Several Few High Sierra Leone **\*** West Africa Few - Low South Africa **\*** Sothern Africa Several Several High Sudan **\*** East Africa Few - Low

Tanzania **\*** East Africa Several Several High Tunisia **\*** North Africa Few - Low Uganda **\*** East Africa Few - Low

Sources: Karekezi, (2002), Allafrica.com, (2000), Akinbami *et al*, (2001), Spore, (2004), Amigun and von

Table 2. Countries with documented biogas producing units in Africa as at 2007

No of small/ medium digester ( 100m3)

Africa Several Few Low

Africa Few - Medium

Africa Few - Low

África Few - Low

Africa Several - Medium

Africa Several Few Medium

No of Large scale digester (>100m3)

Level of technology development

characteristic Region

with a lot of potentials.

Congo-

Country Geographical

 Landlocked Coastal Botswana **\*** Southern

Lesotho **\*** Southern

Malawi **\*** Southern

Namibia **\*** Southern

Swaziland **\*** Southern

Zimbabwe **\*** Southern

Blottnitz, (2007).

Some of the first biogas digesters were set up in Africa in the 1950s in South Africa and Kenya. In other countries such as in Tanzania, biogas digesters were first introduced in 1975 and in others even more recently (South Sudan in 2001). To date, biogas digesters have been installed in several sub-Saharan countries including Burundi, Botswana, Burkina Faso, Cote d'Ivoire, Ethiopia, Ghana, Guinea, Lesotho, Namibia, Nigeria, Rwanda, Zimbabwe, South Africa and Uganda (Winrock International, 2007). Biogas digesters have utilized a variety of inputs such as waste from slaughterhouses, waste in urban landfill sites, industrial waste (such as bagasse from sugar factories), water hyacinth plants, animal dung and human excreta. Biogas digesters have been installed in various places including commercial farms (such as in chicken and dairy farms in Burundi), a public latrine block (in Kibera, Kenya), prisons in Rwanda, and health clinics and mission hospitals (in Tanzania) (Winrock International, 2007). However, by far the most widely attempted model is the household biogas digester – largely using domestic animal excreta (Table 2). This is due to the fact that this technology is closely linked to poverty alleviation and rural development. The biogas produced from these household-level systems has been used mostly for cooking, with some use for lighting.

Global experience shows that biogas technology is a simple and readily usable technology that does not require overtly sophisticated capacity to construct and manage. It has also been recognized as a simple, adaptable and locally acceptable technology for Africa (Gunnerson and Stuckey, 1986; Taleghani and Kia, 2005). There are some cases of successful biogas intervention in Africa, which demonstrate the effectiveness of the technology and its relevance for the region. The lessons learned from biogas experiences in Africa suggest that having a realistic and modest initial introductory phase for Biogas intervention; taking into account the convenience factors in terms of plant operation and functionality; identifying the optimum plant size and subsidy level; and; having provision for design adaptation are key factors for successful biogas implementation in Africa (Biogas for better life, 2007). Biogas technology has multiple beneficial effects.

#### **2.1 Challenges to biogas commercialisation in Africa and possible measures to overcome them**

The implementation of the biogas technology on large scale may be prevented or slowed down by a number of constraints. They may be grouped as follows: political, social-cultural, financial, informational, institutional, technical and training (Omer and Fadalla, 2003, Ni and Nyns, 1996). Some of the difficulties encountered in the development of anaerobic treatment for biogas production in developing countries are in Table 3.

There is lack of coherent biogas technology strategy in many sub-Saharan African countries despite the increase in the price of conventional fuel on a daily basis, and their rising demand mainly to technical and non-technical factors. The main contentious problems of biogas commercialisation in sub-Saharan African countries relate to economics and political will and many site-specific issues. Some of these issues are informed by local dynamics of perceptions; influenced by personal, social and institutional factors and beliefs, as well as internal conflicts, due to perceived environmental, social and ecological risks, that were aggravated by miscommunication and the lack of understanding.

bureaucracy.

technology in Africa.

and support.

Anaerobic Biogas Generation for Rural Area Energy Provision in Africa 43

innovation (Murphy, 2001). The Taka Gas Project in Tanzania (Mbuligwe and Kassenga, 2004) is a very good example of how large-scale biogas technology projects have failed to take off in Africa. The main objective of the Taka Gas Project was to obtain biogas through anaerobic digestion of municipal solid waste from Dar es Salaam city and serve as a model for other urban areas in Africa to emulate. The project was well prepared with analysis of solid waste as feedstock for the project, strategies for operationalising the project, environmental impacts and economic feasibility and other technical and non-technical and socio-economic issues studied for the project but it has never took off the ground due to

The investment cost of even the smallest of the biogas units is prohibitive for most rural households of sub-Saharan Africa. Evidence from the experiences in Eastern and Southern African countries is still limited, but the general consensus is that the larger combined septic tank/biogas units that are run by institutions such as hospitals and schools have proved to be more viable than the small-scale household bio-digesters. There is need for subsidy-led programmes which will be demand-driven and market-oriented to increase the adoption of biogas plants. Subsidies are justified to make up for the difference between ability to pay and the higher societal benefits (maintenance of forest cover, prevention of land degradation, and reduction in emissions of greenhouse gases) and private benefits (reduction in expenditure for firewood and kerosene, savings in time for cooking and firewood collection and health) accruing to users. Besides the expense, many consumers are hesitant to adopt the biogas technology reflecting the lack of public awareness of the relevant issues. To date, this combination of factors has largely stifled the use of biogas

**2.1.2 Political factors affecting biogas production and commercialisation** 

**2.1.3 Technical factors affecting biogas production and commercialisation** 

There are three major types of digesters that have been in use in developing countries: Chinese fixed dome digester, the Indian floating drum digester and the more recent tube digesters. These reactors are small in size (5-10 m3) and mostly used at household level to deliver the energy demand for household cooking and lighting. The advantages of these reactors are that they are inexpensive compared to sophisticated systems, can be built with

The political barriers that exist are mainly in the area of sovereignty rights and the will to initiate national biogas technology programmes. Another problem is the high number of armed conflicts and political instability in the continent which together with the region's debt burden have reduced the region's credibility. Hence, providing capital even for modest investments will prove difficult. African governments need to commit themselves to renewable energy programmes. Government constant commitments to the development and promotion of renewable energy sources have been instrumental in promoting an ambitious alcohol fuel in Brazil, biogas programmes in Europe, China and India. It could be helpful to learn from the experiences gained in the developed world but adapted to the needs and situation in developing countries. However, in some African countries, the hostile social climate and political instability prevent opportunities of international collaboration


Table 3. Some of the difficulties thwarting development of biogas technology in Africa (Mwakaje, 2007; Murphy, 2001, Lettinga, 2001; Lettinga, 1995, Switzenbum, 1995; Tafdrup, 1995; Iza *et al*., 1991)
